(CNN) --Former U.S. weapons inspector David Kay's comments that his team could find no evidence Iraq had stockpiled unconventional weapons before the March invasion drew mixed reactions from three Democratic presidential candidates Sunday.

"It confirms what I have said for a long period of time: that we were misled -- misled not only in the intelligence, but misled in the way that the president took us to war," Sen. John Kerry of Massachusetts said on "Fox News Sunday."

"What this administration has done is play politics with intelligence and really lean on the intelligence community to come up with the answers they've sought," retired Army Gen. Wesley Clark said on NBC's "Meet the Press."

"This administration has hyped the intelligence to get us into Iraq."

But Sen. Joe Lieberman of Connecticut told CNN, "The fact that David Kay now says they weren't there doesn't say [Iraq] never had them."

Lieberman touted his support for the Iraq war as a sign he is prepared to be tough on national security efforts.

"For me, Saddam Hussein was the weapon of mass destruction," he said, referring to the ousted Iraqi president.

All three candidates spoke from New Hampshire, where they were campaigning in advance of Tuesday's primary.

The alleged existence of chemical and biological weapons in Iraq was the centerpiece of the Bush administration's argument for war.

Kay, who stepped town from his CIA post Friday after spending nine months spearheading the search for banned weapons in Iraq, said he does not believe Iraq was producing weapons of mass destruction in the 1990s.

But in an interview Sunday on National Public Radio, Kay said his team found the Iraqi senior leadership "had an intention to continue to pursue their WMD activities. That they, in fact, had a large number of WMD-related activities." (Full story)

Kerry said Secretary of State Colin Powell told the Senate Intelligence Committee that the only rationale for going to war was the existence of weapons of mass destruction.

It was on that basis, Kerry said, that he supported the resolution authorizing the war.

Asked whether he believes President Bush was part of a willful effort to mislead the American people, Kerry said, "I would never suggest that about a president of the United States without adequate evidence. I don't know the answer to it."

Kerry said he thinks Vice President Dick Cheney "exaggerated, clearly. When they talked about weapons of mass destruction that could be deployed in 45 minutes, there were none. When they talked about aerial devices that could deliver, there were none.

"When they talked about the linkage to al Qaeda. ... I think there's been an enormous amount of exaggeration, stretching, deception," Kerry said.

As for whether Powell might have been misleading, Kerry said, "I trust Colin Powell implicitly. He's a friend of mine, and I think he's a terrific person, and I would not want to believe that."

Clark was asked on NBC's "Meet the Press" why he said in the spring he believed there were weapons of mass destruction in Iraq.

"A lot of us who have not been privy to secret intelligence simply listened to what people told us," Clark said.

"Secretary of State [Donald] Rumsfeld told a group of retired generals, shortly before the war, he said, 'I know where 30 percent of the weapons of mass destruction are.'

"Now, when the secretary of defense tells you something like that, you have a tendency to believe him," said Clark, who was NATO supreme commander during the Kosovo air war in 1999.

Clark said the reputation of the presidency has been tarnished around the world: "We've damaged our national credibility on this issue of weapons of mass destruction."

Clark said he did not support the war in Iraq because it distracted focus from the search for terrorist leader Osama bin Laden "and the people who attacked this country."

Lieberman told CNN: "We ought to ask for a full-scale investigation" of what went into the U.S. intelligence community's prewar assessment.